1. Field of the Invention
The present invention relates to the field of biochemistry, and more particularly, to a biochemical analyzer which performs various assays of biological samples and to a method of controlling the internal temperature of the biochemical analyzer.
2. Description of the Related Art
Recently, a biochemical assay technique to diagnose a disease or detect the presence of a cellular component from a trace amount of a fluid sample such as blood or urine is advancing. A microfluidic device that is used in a biochemical assay of a trace amount of a fluid generally includes a chamber containing the fluid, a channel through which the fluid flows, and a valve controlling the flow of the fluid. A device in which an assay including a biochemical reaction is performed on a microchip is called a “biochip”. In particular, a device designed for performing various steps of fluid treatments and manipulations on a single chip is called a “lab-on-a-chip”.
In order to move a fluid in a microfluidic device, a driving pressure is required. The driving pressure may be a capillary pressure or a pressure exerted by a separate pump. Disk type microfluidic devices including a chamber and a channel have recently been proposed, and a fluid movement is caused by a centrifugal force generated by rotating the disk type microfluidic devices. These disk type microfluidic devices are also called as “Lab CDs” or “Lab-on-a-CDs”.
An apparatus configured to provide atmospheric conditions suitable for a measurable biological sample reaction and to detect the reaction results is designated as a “biochemical analyzer”. Meanwhile, in some cases, in order to perform a reaction such as a lysis reaction or to open or close a valve controlling a fluid flow, an energy application is needed. The energy application may be electromagnetic radiation such as laser. For the electromagnetic radiation application, a biochemical analyzer should include an energy source including a laser diode (LD) or the like.
FIGS. 1A and 1B are graphs illustrating the characteristics of a laser diode, specifically the characteristics of a currently commercially available model (Sony SLD 323V) which is a laser diode. Referring to FIGS. 1A and 1B, as an external temperature (Tc) increases, the optical intensity and wavelength of the laser diode increase. In most other laser diodes, in addition to the model Sony SLD 323V, an optimal optical intensity and wavelength for performing a biochemical reaction using a biological sample are achieved at about 25° C.
However, optimal results of a biochemical assay of a biological sample, which is originated from human beings, are achieved at about 36.5-37.5° C. which is similar to the normal body temperature of most people. As such, since the optimal operational temperature condition of an energy source is different from the optimal temperature condition of a biochemical assay of a biological sample, the accuracy of the results of the assays is lowered, and energy consumption for the assays is increased.